The present invention relates an apparatus for precisely measuring eye characteristics and, more particularly, to an eye characteristic measuring apparatus provided with an image forming condition changing unit for properly adjusting illumination and capable of determining an optimum illuminating condition and an optimum light receiving condition.
A known measuring apparatus for measuring the optical characteristics of the eye focuses an illuminating optical system on the light receiving level of a first photodetecting device and focuses a photodetecting optical system on the basis of an optical characteristic (S) determined from the output of the first photodetecting device. Data provided by the known measuring apparatus for measuring the optical characteristics of the eye can be used only for correcting spectacles, and accordingly it does not have a satisfactory performance.
Accordingly, it is an object of the present invention to provide an eye characteristic measuring apparatus capable of providing sufficient data on eye characteristics of the eye.
According to the present invention, an eye characteristic measuring apparatus comprises a first light source that emits light, a first illuminating optical system capable of illuminating a small region of the retina of the eye in a variable illuminating condition, a first photodetecting optical system provided with a first transforming device that divides the reflected light beam into at least seventeen light beams and a first photodetecting device that receives part of reflected light reflected from the retina through the first transforming device, an arithmetic unit that determines the optical characteristics of the eye on the basis of a first signal provided by the first photodetecting device and corresponding to the inclination of the light, and an image forming condition changing unit that changes the respective image forming conditions of the first illuminating optical system and the first photodetecting optical system according to the level of the first signal provided by the first photodetecting device.